The objective of the present study was to determine the incidence of pituitary adenomas (PAs) and the associated rates and causes of mortality in a large population. The study population comprised 2279 patients (1010 women and 1269 men) of all individuals (n = 3321) with pituitary tumors included in the Swedish Cancer Registry between 1958 and 1991. The mean age (±sd) at diagnosis was 52.3 ± 15.7 yr. The age-standardized incidence of PA increased significantly from approximately 6 cases/million inhabitants in 1958 to 11 cases/million in 1991. The age-specific incidence peaked between 60–70 yr of age in both sexes. Excess mortality was found in the study population. The total number of deaths was 842. The standardized mortality ratio (SMR) for the study population was 2.0. The SMR for women (2.3) was significantly (P < 0.01) higher than that for men (1.9). Cardiovascular diseases were the most common cause of mortality among patients, accounting for 346 deaths (SMR, 1.6). The difference between the sexes was significant (men, 1.4; women, 1.8; P < 0.05). Cerebrovascular death occurred in 97 patients (SMR, 2.4), with no significant difference between men (SMR, 2.5) and women (SMR, 2.2). Excess mortality was also observed for tumors, endocrine diseases, and gastrointestinal diseases. These findings suggest that the annual incidence of PA is increasing. Possible explanations are improved diagnostic skill and/or increased awareness of pituitary diseases among physicians. However, a real increase in the incidence of PA cannot be ruled out.